Any difference between using shutdown.sh and kill -15 <PID>

We're using kill -15 in our shutdown scripts to stop JBoss 5.2 instances on Linux vs using the shutdown.sh -s jnp://localhost: -u shutdownuser -p .

Is there any real difference between them? I know the shutdown.sh script has more functionality but do they both perform the same graceful shutdown of a JVM?

I've seen this article here: https://access.redhat.com/solutions/18601 but a developer says the shutdown.sh is preferred but isn't sure on the 'why' part.

Thanks!